.TH "Memory Utility Routines" 3 "24 Jan 2005" "net-snmp" \" -*- nroff -*-
.ad l
.nh
.SH NAME
Memory Utility Routines \- 
.SS "Defines"

.in +1c
.ti -1c
.RI "#define \fBSNMP_MAXPATH\fP   1024		/* Should be safe enough */"
.br
.ti -1c
.RI "#define \fBSNMP_MAXBUF\fP   (1024 * 4)"
.br
.ti -1c
.RI "#define \fBSNMP_MAXBUF_MEDIUM\fP   1024"
.br
.ti -1c
.RI "#define \fBSNMP_MAXBUF_SMALL\fP   512"
.br
.ti -1c
.RI "#define \fBSNMP_MAXBUF_MESSAGE\fP   1500"
.br
.ti -1c
.RI "#define \fBSNMP_MAXOID\fP   64"
.br
.ti -1c
.RI "#define \fBSNMP_MAX_CMDLINE_OIDS\fP   128"
.br
.ti -1c
.RI "#define \fBSNMP_FILEMODE_CLOSED\fP   0600"
.br
.ti -1c
.RI "#define \fBSNMP_FILEMODE_OPEN\fP   0644"
.br
.ti -1c
.RI "#define \fBBYTESIZE\fP(bitsize)   ((bitsize + 7) >> 3)"
.br
.ti -1c
.RI "#define \fBROUNDUP8\fP(x)   ( ( (x+7) >> 3 ) * 8 )"
.br
.ti -1c
.RI "#define \fBSNMP_FREE\fP(s)   do { if (s) { free((void *)s); s=NULL; } } while(0)"
.br
.RI "\fIFrees a pointer only if it is !NULL and sets its value to NULL. \fP"
.ti -1c
.RI "#define \fBSNMP_SWIPE_MEM\fP(n, s)   do { if (n) free((void *)n); n = s; s=NULL; } while(0)"
.br
.RI "\fIFrees pointer n only if it is !NULL, sets n to s and sets s to NULL. \fP"
.ti -1c
.RI "#define \fBSNMP_MALLOC_STRUCT\fP(s)   (struct s *) calloc(1, sizeof(struct s))"
.br
.RI "\fIMallocs memory of sizeof(struct s), zeros it and returns a pointer to it. \fP"
.ti -1c
.RI "#define \fBSNMP_MALLOC_TYPEDEF\fP(td)   (td *) calloc(1, sizeof(td))"
.br
.RI "\fIMallocs memory of sizeof(t), zeros it and returns a pointer to it. \fP"
.ti -1c
.RI "#define \fBSNMP_ZERO\fP(s, l)   do { if (s) memset(s, 0, l); } while(0)"
.br
.RI "\fIZeros l bytes of memory starting at s. \fP"
.ti -1c
.RI "#define \fBTOUPPER\fP(c)   (c >= 'a' && c <= 'z' ? c - ('a' - 'A') : c)"
.br
.ti -1c
.RI "#define \fBTOLOWER\fP(c)   (c >= 'A' && c <= 'Z' ? c + ('a' - 'A') : c)"
.br
.ti -1c
.RI "#define \fBHEX2VAL\fP(s)   ((isalpha(s) ? (TOLOWER(s)-'a'+10) : (TOLOWER(s)-'0')) & 0xf)"
.br
.ti -1c
.RI "#define \fBVAL2HEX\fP(s)   ( (s) + (((s) >= 10) ? ('a'-10) : '0') )"
.br
.ti -1c
.RI "#define \fBSNMP_MAX\fP(a, b)   ((a) > (b) ? (a) : (b))"
.br
.RI "\fIComputers the maximum of a and b. \fP"
.ti -1c
.RI "#define \fBSNMP_MIN\fP(a, b)   ((a) > (b) ? (b) : (a))"
.br
.RI "\fIComputers the minimum of a and b. \fP"
.ti -1c
.RI "#define \fBFALSE\fP   0"
.br
.ti -1c
.RI "#define \fBTRUE\fP   1"
.br
.ti -1c
.RI "#define \fBQUITFUN\fP(e, l)"
.br
.ti -1c
.RI "#define \fBDIFFTIMEVAL\fP(now, then, diff)"
.br
.ti -1c
.RI "#define \fBUSM_LENGTH_OID_TRANSFORM\fP   10"
.br
.ti -1c
.RI "#define \fBISTRANSFORM\fP(ttype, toid)"
.br
.ti -1c
.RI "#define \fBENGINETIME_MAX\fP   2147483647      /* ((2^31)-1) */"
.br
.ti -1c
.RI "#define \fBENGINEBOOT_MAX\fP   2147483647      /* ((2^31)-1) */"
.br
.in -1c
.SS "Typedefs"

.in +1c
.ti -1c
.RI "typedef void * \fBmarker_t\fP"
.br
.in -1c
.SS "Functions"

.in +1c
.ti -1c
.RI "int \fBsnmp_realloc\fP (u_char **buf, size_t *buf_len)"
.br
.RI "\fIThis function increase the size of the buffer pointed at by *buf, which is initially of size *buf_len. \fP"
.ti -1c
.RI "void \fBfree_zero\fP (void *buf, size_t size)"
.br
.RI "\fIzeros memory before freeing it. \fP"
.ti -1c
.RI "u_char * \fBmalloc_random\fP (size_t *size)"
.br
.RI "\fIReturns pointer to allocaed & set buffer on success, size contains number of random bytes filled. \fP"
.ti -1c
.RI "u_char * \fBmalloc_zero\fP (size_t size)"
.br
.ti -1c
.RI "int \fBmemdup\fP (u_char **to, const u_char *from, size_t size)"
.br
.RI "\fIDuplicates a memory block. \fP"
.ti -1c
.RI "u_int \fBbinary_to_hex\fP (const u_char *input, size_t len, char **output)"
.br
.RI "\fIconverts binary to hexidecimal \fP"
.ti -1c
.RI "int \fBnetsnmp_hex_to_binary\fP (u_char **buf, size_t *buf_len, size_t *out_len, int allow_realloc, const char *hex, const char *delim)"
.br
.RI "\fIconvert an ASCII hex string (with specified delimiters) to binary \fP"
.ti -1c
.RI "int \fBsnmp_hex_to_binary\fP (u_char **buf, size_t *buf_len, size_t *out_len, int allow_realloc, const char *hex)"
.br
.RI "\fIconvert an ASCII hex string to binary \fP"
.ti -1c
.RI "int \fBhex_to_binary2\fP (const u_char *input, size_t len, char **output)"
.br
.RI "\fIhex_to_binary2 \fP"
.ti -1c
.RI "int \fBsnmp_decimal_to_binary\fP (u_char **buf, size_t *buf_len, size_t *out_len, int allow_realloc, const char *decimal)"
.br
.ti -1c
.RI "int \fBsnmp_strcat\fP (u_char **buf, size_t *buf_len, size_t *out_len, int allow_realloc, const u_char *s)"
.br
.ti -1c
.RI "char * \fBnetsnmp_strdup_and_null\fP (const u_char *from, size_t from_len)"
.br
.RI "\fIcopies a (possible) unterminated string of a given length into a new buffer and null terminates it as well (new buffer MAY be one byte longer to account for this \fP"
.ti -1c
.RI "void \fBdump_chunk\fP (const char *debugtoken, const char *title, const u_char *buf, int size)"
.br
.ti -1c
.RI "char * \fBdump_snmpEngineID\fP (const u_char *buf, size_t *buflen)"
.br
.ti -1c
.RI "marker_t \fBatime_newMarker\fP (void)"
.br
.RI "\fIcreate a new time marker. \fP"
.ti -1c
.RI "void \fBatime_setMarker\fP (marker_t pm)"
.br
.RI "\fIset a time marker. \fP"
.ti -1c
.RI "long \fBatime_diff\fP (marker_t first, marker_t second)"
.br
.RI "\fIReturns the difference (in msec) between the two markers. \fP"
.ti -1c
.RI "u_long \fBuatime_diff\fP (marker_t first, marker_t second)"
.br
.RI "\fIReturns the difference (in u_long msec) between the two markers. \fP"
.ti -1c
.RI "u_long \fBuatime_hdiff\fP (marker_t first, marker_t second)"
.br
.RI "\fIReturns the difference (in u_long 1/100th secs) between the two markers (functionally this is what sysUpTime needs). \fP"
.ti -1c
.RI "int \fBatime_ready\fP (marker_t pm, int deltaT)"
.br
.RI "\fITest: Has (marked time plus delta) exceeded current time (in msec) ? Returns 0 if test fails or cannot be tested (no marker). \fP"
.ti -1c
.RI "int \fBuatime_ready\fP (marker_t pm, unsigned int deltaT)"
.br
.RI "\fITest: Has (marked time plus delta) exceeded current time (in msec) ? Returns 0 if test fails or cannot be tested (no marker). \fP"
.ti -1c
.RI "int \fBmarker_tticks\fP (marker_t pm)"
.br
.RI "\fIReturn the number of timeTicks since the given marker. \fP"
.ti -1c
.RI "int \fBtimeval_tticks\fP (struct timeval *tv)"
.br
.ti -1c
.RI "char * \fBnetsnmp_getenv\fP (const char *name)"
.br
.RI "\fINon Windows: Returns a pointer to the desired environment variable or NULL if the environment variable does not exist. \fP"
.in -1c
.SH "Define Documentation"
.PP 
.SS "#define DIFFTIMEVAL(now, then, diff)"
.PP
\fBValue:\fP.nf
{                                                       \
        now.tv_sec--;                                   \
        now.tv_usec += 1000000L;                        \
        diff.tv_sec  = now.tv_sec  - then.tv_sec;       \
        diff.tv_usec = now.tv_usec - then.tv_usec;      \
        if (diff.tv_usec > 1000000L){                   \
                diff.tv_usec -= 1000000L;               \
                diff.tv_sec++;                          \
        }                                               \
}
.fi
.PP
Definition at line 121 of file tools.h.
.SS "#define ISTRANSFORM(ttype, toid)"
.PP
\fBValue:\fP.nf
!snmp_oid_compare(ttype, USM_LENGTH_OID_TRANSFORM,            \
                usm ## toid ## Protocol, USM_LENGTH_OID_TRANSFORM)
.fi
.PP
Definition at line 140 of file tools.h.
.SS "#define QUITFUN(e, l)"
.PP
\fBValue:\fP.nf
if ( (e) != SNMPERR_SUCCESS) {   \
                rval = SNMPERR_GENERR;  \
                goto l ;                \
        }
.fi
.PP
Definition at line 108 of file tools.h.
.SS "#define SNMP_FREE(s)   do { if (s) { free((void *)s); s=NULL; } } while(0)"
.PP
Frees a pointer only if it is !NULL and sets its value to NULL. Definition at line 54 of file tools.h.
.PP
Referenced by build_oid_segment(), fprint_description(), fprint_objid(), fprint_variable(), init_mib(), netsnmp_cache_reqinfo_extract(), netsnmp_cache_reqinfo_insert(), netsnmp_create_handler(), netsnmp_fixup_mib_directory(), netsnmp_free_all_list_data(), netsnmp_free_delegated_cache(), netsnmp_free_list_data(), netsnmp_getenv(), netsnmp_handler_free(), netsnmp_handler_registration_free(), netsnmp_register_old_api(), netsnmp_set_mib_directory(), netsnmp_set_row_column(), netsnmp_table_build_oid_from_index(), netsnmp_table_data_delete_row(), netsnmp_table_data_set_helper_handler(), netsnmp_table_dataset_delete_data(), netsnmp_table_iterator_helper_handler(), read_objid(), shutdown_mib(), snmp_unregister_callback(), and unregister_config_handler().
.SS "#define SNMP_MALLOC_STRUCT(s)   (struct s *) calloc(1, sizeof(struct s))"
.PP
Mallocs memory of sizeof(struct s), zeros it and returns a pointer to it. Definition at line 65 of file tools.h.
.PP
Referenced by snmp_alarm_register(), and snmp_alarm_register_hr().
.SS "#define SNMP_MALLOC_TYPEDEF(td)   (td *) calloc(1, sizeof(td))"
.PP
Mallocs memory of sizeof(t), zeros it and returns a pointer to it. Definition at line 69 of file tools.h.
.PP
Referenced by netsnmp_baby_steps_handler_get(), netsnmp_cache_create(), netsnmp_container_table_handler_get(), netsnmp_create_data_list(), netsnmp_create_delegated_cache(), netsnmp_create_handler(), netsnmp_create_table_data(), netsnmp_create_table_data_row(), netsnmp_create_table_data_set(), netsnmp_handler_registration_create(), netsnmp_mark_row_column_writable(), netsnmp_mode_end_call_add_mode_callback(), netsnmp_oid_stash_create_sized_node(), netsnmp_old_api_helper(), netsnmp_register_auto_data_table(), netsnmp_register_mib_table_row(), netsnmp_register_old_api(), netsnmp_register_save_list(), netsnmp_register_table_data_set(), netsnmp_set_row_column(), netsnmp_table_container_register(), netsnmp_table_data_set_helper_handler(), netsnmp_table_iterator_helper_handler(), netsnmp_table_set_add_default_row(), and table_helper_handler().
.SS "#define SNMP_MAX(a, b)   ((a) > (b) ? (a) : (b))"
.PP
Computers the maximum of a and b. Definition at line 86 of file tools.h.
.PP
Referenced by netsnmp_register_table_data_set().
.SS "#define SNMP_MIN(a, b)   ((a) > (b) ? (b) : (a))"
.PP
Computers the minimum of a and b. Definition at line 90 of file tools.h.
.PP
Referenced by netsnmp_oid_find_prefix(), netsnmp_register_table_data_set(), and netsnmp_table_data_helper_handler().
.SS "#define SNMP_SWIPE_MEM(n, s)   do { if (n) free((void *)n); n = s; s=NULL; } while(0)"
.PP
Frees pointer n only if it is !NULL, sets n to s and sets s to NULL. Definition at line 58 of file tools.h.
.SS "#define SNMP_ZERO(s, l)   do { if (s) memset(s, 0, l); } while(0)"
.PP
Zeros l bytes of memory starting at s. Definition at line 73 of file tools.h.
.SH "Function Documentation"
.PP 
.SS "long atime_diff (marker_t first, marker_t second)"
.PP
Returns the difference (in msec) between the two markers. Definition at line 792 of file tools.c.
.PP
Referenced by atime_ready(), and marker_tticks().
.SS "marker_t atime_newMarker (void)"
.PP
create a new time marker. NOTE: Caller must free time marker when no longer needed. Definition at line 768 of file tools.c.
.PP
Referenced by atime_ready(), marker_tticks(), netsnmp_stash_cache_update(), and uatime_ready().
.SS "int atime_ready (marker_t pm, int deltaT)"
.PP
Test: Has (marked time plus delta) exceeded current time (in msec) ? Returns 0 if test fails or cannot be tested (no marker). Definition at line 847 of file tools.c.
.PP
References atime_diff(), and atime_newMarker().
.PP
Referenced by netsnmp_cache_check_expired(), and netsnmp_stash_cache_update().
.SS "void atime_setMarker (marker_t pm)"
.PP
set a time marker. Definition at line 779 of file tools.c.
.PP
Referenced by netsnmp_stash_cache_update().
.SS "u_int binary_to_hex (const u_char * input, size_t len, char ** output)"
.PP
converts binary to hexidecimal \fBParameters:\fP
.RS 4
\fI*input\fP Binary data. 
.br
\fIlen\fP Length of binary data. 
.br
\fI**output\fP NULL terminated string equivalent in hex.
.RE
.PP
\fBReturns:\fP
.RS 4
olen Length of output string not including NULL terminator.
.RE
.PP
FIX Is there already one of these in the UCD SNMP codebase? The old one should be used, or this one should be moved to snmplib/snmp_api.c. Definition at line 285 of file tools.c.
.SS "void free_zero (void * buf, size_t size)"
.PP
zeros memory before freeing it. \fBParameters:\fP
.RS 4
\fI*buf\fP Pointer at bytes to free. 
.br
\fIsize\fP Number of bytes in buf. 
.RE
.PP
Definition at line 183 of file tools.c.
.PP
Referenced by hex_to_binary2(), and malloc_random().
.SS "int hex_to_binary2 (const u_char * input, size_t len, char ** output)"
.PP
hex_to_binary2 \fBParameters:\fP
.RS 4
\fI*input\fP Printable data in base16. 
.br
\fIlen\fP Length in bytes of data. 
.br
\fI**output\fP Binary data equivalent to input.
.RE
.PP
\fBReturns:\fP
.RS 4
SNMPERR_GENERR on failure, otherwise length of allocated string.
.RE
.PP
Input of an odd length is right aligned.
.PP
FIX Another version of 'hex-to-binary' which takes odd length input strings. It also allocates the memory to hold the binary data. Should be integrated with the official hex_to_binary() function. Definition at line 322 of file tools.c.
.PP
References free_zero().
.SS "u_char* malloc_random (size_t * size)"
.PP
Returns pointer to allocaed & set buffer on success, size contains number of random bytes filled. buf is NULL and *size set to KMT error value upon failure.
.PP
\fBParameters:\fP
.RS 4
\fIsize\fP Number of bytes to malloc() and fill with random bytes.
.RE
.PP
\fBReturns:\fP
.RS 4
a malloced buffer 
.RE
.PP
Definition at line 203 of file tools.c.
.PP
References free_zero().
.SS "int marker_tticks (marker_t pm)"
.PP
Return the number of timeTicks since the given marker. Definition at line 895 of file tools.c.
.PP
References atime_diff(), and atime_newMarker().
.SS "int memdup (u_char ** to, const u_char * from, size_t size)"
.PP
Duplicates a memory block. Copies a existing memory location from a pointer to another, newly malloced, pointer.
.PP
\fBParameters:\fP
.RS 4
\fIto\fP Pointer to allocate and copy memory to. 
.br
\fIfrom\fP Pointer to copy memory from. 
.br
\fIsize\fP Size of the data to be copied.
.RE
.PP
\fBReturns:\fP
.RS 4
SNMPERR_SUCCESS on success, SNMPERR_GENERR on failure. 
.RE
.PP
Definition at line 234 of file tools.c.
.PP
Referenced by netsnmp_handler_registration_create(), netsnmp_handler_registration_dup(), netsnmp_register_old_api(), netsnmp_set_row_column(), netsnmp_table_data_clone_row(), netsnmp_table_data_set_clone_row(), and netsnmp_table_set_add_default_row().
.SS "char* netsnmp_getenv (const char * name)"
.PP
Non Windows: Returns a pointer to the desired environment variable or NULL if the environment variable does not exist. Windows: Returns a pointer to the desired environment variable if it exists. If it does not, the variable is looked up in the registry in HKCU-SNMP or HKLM-SNMP (whichever it finds first) and stores the result in the environment variable. It then returns a pointer to environment variable. Definition at line 923 of file tools.c.
.PP
References SNMP_FREE.
.PP
Referenced by init_mib(), netsnmp_fixup_mib_directory(), netsnmp_get_mib_directory(), and read_config_store().
.SS "int netsnmp_hex_to_binary (u_char ** buf, size_t * buf_len, size_t * out_len, int allow_realloc, const char * hex, const char * delim)"
.PP
convert an ASCII hex string (with specified delimiters) to binary \fBParameters:\fP
.RS 4
\fIbuf\fP address of a pointer (pointer to pointer) for the output buffer. If allow_realloc is set, the buffer may be grown via snmp_realloc to accomodate the data.
.br
\fIbuf_len\fP pointer to a size_t containing the initial size of buf.
.br
\fIout_len\fP On input, a pointer to a size_t indicating an offset into buf. The binary data will be stored at this offset. On output, this pointer will have updated the offset to be the first byte after the converted data.
.br
\fIallow_realloc\fP If true, the buffer can be reallocated. If false, and the buffer is not large enough to contain the string, an error will be returned.
.br
\fIhex\fP pointer to hex string to be converted. May be prefixed by '0x' or '0X'.
.br
\fIdelim\fP point to a string of allowed delimiters between bytes. If not specified, any non-hex characters will be an error.
.RE
.PP
\fBReturn values:\fP
.RS 4
\fI1\fP success 
.br
\fI0\fP error 
.RE
.PP
Definition at line 423 of file tools.c.
.PP
References snmp_realloc().
.PP
Referenced by snmp_hex_to_binary().
.SS "char* netsnmp_strdup_and_null (const u_char * from, size_t from_len)"
.PP
copies a (possible) unterminated string of a given length into a new buffer and null terminates it as well (new buffer MAY be one byte longer to account for this Definition at line 253 of file tools.c.
.PP
Referenced by netsnmp_table_data_set_helper_handler().
.SS "int snmp_hex_to_binary (u_char ** buf, size_t * buf_len, size_t * out_len, int allow_realloc, const char * hex)"
.PP
convert an ASCII hex string to binary \fBNote:\fP
.RS 4
This is a wrapper which calls netsnmp_hex_to_binary with a delimiter string of ' '.
.RE
.PP
See netsnmp_hex_to_binary for parameter descriptions.
.PP
\fBReturn values:\fP
.RS 4
\fI1\fP success 
.br
\fI0\fP error 
.RE
.PP
Definition at line 482 of file tools.c.
.PP
References netsnmp_hex_to_binary().
.SS "int snmp_realloc (u_char ** buf, size_t * buf_len)"
.PP
This function increase the size of the buffer pointed at by *buf, which is initially of size *buf_len. Contents are preserved **AT THE BOTTOM END OF THE BUFFER**. If memory can be (re-)allocated then it returns 1, else it returns 0.
.PP
\fBParameters:\fP
.RS 4
\fIbuf\fP pointer to a buffer pointer 
.br
\fIbuf_len\fP pointer to current size of buffer in bytes
.RE
.PP
\fBNote:\fP
.RS 4
The current re-allocation algorithm is to increase the buffer size by whichever is the greater of 256 bytes or the current buffer size, up to a maximum increase of 8192 bytes. 
.RE
.PP
Definition at line 119 of file tools.c.
.PP
Referenced by _sprint_hexstring_line(), netsnmp_hex_to_binary(), sprint_realloc_asciistring(), sprint_realloc_ipaddress(), sprint_realloc_networkaddress(), and sprint_realloc_octet_string().
.SS "u_long uatime_diff (marker_t first, marker_t second)"
.PP
Returns the difference (in u_long msec) between the two markers. Definition at line 809 of file tools.c.
.PP
Referenced by uatime_ready().
.SS "u_long uatime_hdiff (marker_t first, marker_t second)"
.PP
Returns the difference (in u_long 1/100th secs) between the two markers (functionally this is what sysUpTime needs). Definition at line 827 of file tools.c.
.SS "int uatime_ready (marker_t pm, unsigned int deltaT)"
.PP
Test: Has (marked time plus delta) exceeded current time (in msec) ? Returns 0 if test fails or cannot be tested (no marker). Definition at line 869 of file tools.c.
.PP
References atime_newMarker(), and uatime_diff().
